What is the right way to free a std::vector of pointers in C++?

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I searched StackOverflow but couldn't find the answer to this question.

Suppose I have a std::vector<Day *> vector_day - that is - a vector of pointers to Day object. Now I push_back to vector_day many elements:

vector_day.push_back(new Day(12));
vector_day.push_back(new Day(99));
vector_day.push_back(new Day(71));
...

Now at some point I no longer need vector_day. What is the right way to free the memory?

It this the correct way:

for (std::vector<Day *>::iterator i = vector_day.begin(); i != vector_day.end(); ++i) {
    delete *i;
}

Doesn't this invalidate the vector on each deletion? I am very confused.

delete-operator vector memory containers c++
10 Answers

Another way of iterating + deleting is by using while(!empty) loop. The advantage of this technique is that an element is removed from container first, deleted afterwords. This is safe for any container:

while (!vector_day.empty()) {
    Day* day = vector_day.back();
    vector_day.pop_back();
    delete day;
}
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